AWOS is a fast, highly optimized operating
environment that strives to be POSIX compliant.
Care is taken to ensure that it can run on very
old hardware, yet still allow it to take advantage
of the newest platforms.

AberSim makes use of the Motorola as11 assembler
and the sim68xx simulator to provide a graphical
integrated development and simulation environment
for the 68HC11 processor. It is designed to be
simple for additional simulated hardware to be
created.

Aasm is an advanced modular assembler designed to support several target architectures. It has been designed to be easily extended. Its global architecture takes advantages of dynamic libraries to provide input, assembler and output modules. The input module supports Intel syntax (like nasm, tasm, masm, etc.). The x86 assembler module supports all opcodes up to P6 including MMX, SSE and 3DNow! extensions. F-CPU and SPARC assembler modules are under development. Several output modules are available for ELF, COFF, IntelHex, and raw binary formats. Advanced features include symbol scopes, an expressions engine, big integer support, macro capability, and numerous and accurate warning messages (over 300).

Alpaca is a multitasking operating system for Z-80 based arcade hardware. It has been designed to run on both Pac-Man and Pengo based arcade machines, but can easily be ported to other machines with similar architectures. It supports four concurrently running processes, task switching, simple inter-process messaging, semaphores, and a basic window-based graphical interface.

AntiJOP is an anti-malware solution that recodes assembly language to remove JOP attack gadgets. JOP attacks on x86 often hinge on the availability of 0xFF bytes in preexisting code, which can be co-opted to serve as register-indirect call instructions. AntiJOP removes instances of 0xFF bytes that may exist, for example, in immediate values, MOD/RM bytes, etc.